Motor drives and other power conversion systems operate using power from AC power sources, and may include an input filter to reduce switching noise associated with operation of the power converter, particularly to control total harmonic distortion (THD) generated by high frequency operation of active front end (AFE) rectifiers. The input filter employed in these converters often includes an inductor-capacitor (LC) or an LCL (inductance-capacitance-inductance) circuit associated with each AC input phase to control the harmonic content of a power grid. LCL and LC filter circuits may interact with the power conversion circuitry under circumstances leading to resonant conditions which may damage or degrade filter circuit components and other elements of the power converter. Such degradation may be costly in terms of replacement component costs, labor for inspection and replacement, as well as downtime for the power conversion system and any associated machinery. In addition, continued operation of the converter with internal resonant conditions degrades system efficiency and may inhibit the ability to properly drive a load. Thus far, however, assessing power converter resonance has been difficult and these conditions are not easily identifiable by operators or service personnel.